my protagonist gets jumped in a cave by Goblins armed with Composite bows from about 30 feet away my protagonist has full plate and a kite shield, the goblins are decent archers but startled and protagonist is able to get his guard up.

3 Answers
3

If the goblins are the typical small creatures, most likely anywhere that has a solid plate.

With their small arms, they wouldn't get very much of a draw on the bow. The only thing that makes the bows even slightly viable is the fact that they are composite bows and that they will have a slight multiplier on the strength of their draw.

The troublesome parts will be joints and other gaps.

This isn't to say that all the arrows will actually bounce off. Most should. However some may hit straight enough to penetrate the outer armor but they shouldn't have enough energy left to get through the undercoat (chain and/or padded quilt). As long as the arrowheads aren't poisoned, the most he'll get are scratches as he moves or minor cuts.

The one thing that I can see is if, as a small creature, if they are close, they will be firing upward and that angle will allow them to shoot up into the overlaps (if the torso is articulated).

$\begingroup$It's not about the size of the archer (so you might want to put back your part about bouncing off just about anywhere, I feel that it's accurate for the most part.) The main problems with that other answer are that it indicates shields as a primary defense for a fully armored combatant, which is not common, and when it was done it was usually for ceremony or battlefield communication, not defense. Also, their answer uses vague testing references (which I suspect are not accurate) as well as alternative materials and construction which compromise the validity of the conclusions.$\endgroup$
– DalilaOct 19 '18 at 21:00

$\begingroup$@ShadoCat Goblins are about 4 feet tall but are strong enough to strangle an adult human$\endgroup$
– AxenOct 19 '18 at 23:12

$\begingroup$The overlaps are very tight (for well made armor) and require a lot of presicion, and Levering to enter. Over laps are not a viable spot for the arrows to pierce. The eye holes, in the other hand are$\endgroup$
– Garret GangOct 20 '18 at 21:47

Based on live testing of modern reproduction plate, using modern 14 gauge aluminum (comparable strength to common medieval plate) and a child's 70 lb draw crossbow, any direct hit will go right through plate. Plate was good against glancing hits (which most are).

Update based questions raised in comments

This particular (uncontrolled) test was done with a reproduction medieval crossbow that had been custom built and scaled for use by a 6 year old child. It was the result of a discussion over which was better defense against an arrow at an SCA event.

Since there were lots of pieces of armor present, two of the participants put their armor up for the test, one chain mail and one plate. The armor was propped up by a hay bale for the impromptu test. The quarrel penetrated front and rear, and through the back of the hay bale (where it was conveniently retrieved).

The armor was of uniform thickness, so it was not a perfect reproduction. 14 guage sheet metal is what it is.

In contrast, the shots fired against chain mail (made from modern coat hanger wire) did not penetrate. The mail protected much like kevlar does, by yielding and absorbing energy over distance.

$\begingroup$"strength" can have many different meanings, not all of which apply to the effectiveness of armor, so I highly doubt that modern aluminum armor's defensive capabilities can be reasonably compared to medieval steel armor. Also, many testing techniques for medieval weapons and armor are highly suspect in their methodologies, so I would not put much stock in them without knowing the specific methods used for such a "test". Also, when a particular soldier was in Full Plate armor, they rarely had a need, and so rarely, if ever, used a shield. Their armor WAS the shield$\endgroup$
– DalilaOct 19 '18 at 20:30

$\begingroup$@Dalila, the biggest problem is that modern tests generally use modern bows or English long bows which traded speed (number of shots) for power. The long bows could punch through plate armor (and stick out through the back). It's just that it was a specialized bow.$\endgroup$
– ShadoCatOct 19 '18 at 20:54

$\begingroup$@ShadoCat I disagree. I believe the most common problem with testing is the mis-use of the actual targets. Targets often misrepresent a human in armor. It is MUCH easier to penetrate armor when it is secured in place than it is when it's on a moving and flexible human bag of mostly water. The next biggest flaw is that the armor analogues are often not representative of actual armor. Modern manufacturing allows uniform thickness, while historic armor was often much thicker in the front/middle (think sternum) than it was the edges (ribs under the armpits), let alone the actual metal used$\endgroup$
– DalilaOct 19 '18 at 21:03

$\begingroup$Umm, the most recent test I saw used a 250 lb draw crossbow, and a wooden bolt a little thicker then a quarter inch, it didn't deflect off the plate, as it exploded into a cloud of splinters.$\endgroup$
– Garret GangOct 27 '18 at 1:45